In order to meet the demand for wireless data traffic soring since the 4th generation (4G) communication system came to the market, there are ongoing efforts to develop enhanced 5th generation (5G) communication systems or pre-5G communication systems. For the reasons, the 5G communication system or pre-5G communication system is called the beyond 4G network communication system or post long-term evolution (LTE) system.
For higher data transmit rates, 5G communication systems are considered to be implemented on ultra-high frequency bands (mmWave), such as, e.g., 60 GHz. To mitigate pathloss on the ultra-high frequency band and increase the reach of radio waves, the following techniques are taken into account for the 5G communication system: beamforming, massive multi-input multi-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna, analog beamforming, and large scale antenna.
Also being developed are various technologies for the 5G communication system to have an enhanced network, such as evolved or advanced small cell, cloud radio access network (cloud RAN), ultra-dense network, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, coordinated multi-point (CoMP), and interference cancellation.
Other techniques being developed for 5G systems are among hybrid frequency shift keying (FSK) and quadrature amplitude modulation (QAM) (FQAM) and sliding window superposition coding (SWSC), as advanced coding modulation (ACM) schemes, and filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA), as advanced access techniques.
Diversified wireless techniques are recently under development to handle soaring broadband service subscribers and offer better service quality. The 3rd Generation Partnership Project 2 (3GPP2) has developed code division multiple access 2000 (CDMA2000), lx evolution data optimized (1×EVDO), and ultra-mobile broadband (UMB) systems, and the 3GPP has developed wide-band CDMA (WCDMA), high speed packet access (HSPA), and long term evolution (LTE) systems. The institute of electrical and electronics engineer (IEEE) has developed mobile worldwide interoperability for microwave access (WiMAX) systems. As more and more communication services are provided through mobile communication systems, there is increasing demand for high-capacity, high-throughput, low-latency, and more reliable mobile communication systems.
One noticeable candidate is super mobile broadband (SMB) that is based on radio waves with a wavelength range from 1 mm to 10 mm which corresponds to a radio frequency band from 30 GHz to 300 GHz. This next-generation mobile communication technology draws attention particularly because of its availability of wide mmWave bands. As set forth in the paper “An introduction to Millimeter-Wave Broadband Systems” authored by Zhouye Pi and Farooq Khan, an SMB network consists of multiple SMB base stations that cover a certain geographical area. To ensure better coverage, the SMB base stations need to be deployed more densely than macro cellular base stations. Generally, substantially the same inter-site distance is recommended in arranging micro cells or pico cells in a city environment. High-frequency radio waves may not reach a long distance because they suffer from more propagation loss.
Beamforming may be used to address such issue. Beamforming techniques may be classified into transmission (TX) beamforming that is performed on the TX end and reception (RX) beamforming that is performed on the RX end. Typically, TX beamforming uses multiple antennas to collectively direct radio waves to a particular spot, raising directivity. In such context, the aggregation of the multiple antennas may be denoted an antenna array, and each antenna in the antenna array may be denoted an array element. The antenna array may be configured in various forms, e.g., a linear array or planar array. The use of TX beamforming may lead to better signal directivity and increased propagation distance. Further, TX beamforming may reduce signal interference at the RX end because most of the signals from the antenna array are directed at the RX end. The RX end may perform beamforming on RX signals using an RX antenna array. RX beamforming allows radio waves to concentrate in a particular direction, increasing the strength of RX signals that are transmitted in the direction while getting rid of signals that have been sent in different directions. By so doing, RX beamforming may block interference signals.
In such a beamforming system, a user equipment (UE) receives a DL grant and relevant data using the best RX beam when receiving downlink (DL) data. A base station transmits a DL grant and relevant data using the best TX beam. In the beamforming system, the base station transmits an uplink (UL) grant using the best TX beam when transmitting UL data, and the UE receives the UL grant using the best RX beam. Upon the UL grant, the UE transmits UL data using the best TX beam.
The beamforming system allocates resources based on the SPS to respond to periodic traffic which may occur upon using, e.g., voice over internet protocol (VoIP). The SPS-based resource allocation in the beamforming system contributes to reducing control overhead.
Now described with reference to FIGS. 1 and 2 is the operation of a beamforming system that allocates resources based on the SPS.
FIG. 1 illustrates the operation of the beamforming system that allocates resources based on DL SPS.
Referring to FIG. 1, two users (e.g., UE1 and UE2) are using DL SPS. UE1 and UE2 are allocated to have DL SPS resources within the same subframe 100.
In the beamforming system, UE1 and UE2 receive DL data within the allocated DL resources using their respective best RX beams (e.g., DL RX beams). A base station uses the best TX beam, e.g., the optimal DL TX beam known by UE1 and UE2, to transmit data to UE1 and UE2 within the allocated DL grant. Where UE1 and UE2 are located within the same optimal DL TX beam coverage, UE1 and UE2 are allocated their respective DL SPS resources in the same subframe 100. Even when UE1 and UE2 are located in different optimal DL TX beam coverage ranges, and the base station has separate antenna arrays for simultaneously transmitting to the UEs, UE1 and UE2 may be allocated their respective SPS resources in the same subframe 100.
However, the movement of the UEs may frequently vary the TX beams/RX beams that are used for transmission/reception in the beamforming system. If the TX beam of the base station varies, the allocated DL SPS resource allocations may be required to change. For example, where the DL TX beam covering UE1 and UE2 is varied when the base station lacks separate antenna arrays to support UE1 and UE2, the allocated DL SPS resource allocations need to be varied for UE1 and UE2. The variations in the optimal RX beams of the UEs do not require variations in the allocated DL SPS resource allocations. The allocated DL SPS resource allocation may be required to frequently update depending on the width of TX beam of the base station and the movement of the UEs, and this may defeat the purpose of SPS.
Similar to the operation of allocating SPS on DL, the operation of allocating resources based on SPS is carried out on UL as well.
FIG. 2 illustrates the operation of the beamforming system that allocates resources based on UL SPS.
Referring to FIG. 2, when two users (e.g., UE1 and UE2) are using DL SPS, UE1 and UE2 are allocated to have UL SPS resources within the same subframe 200.
Where UE1 and UE2 are located within the same optimal UL RX beam coverage, UE1 and UE2 are allocated their respective UL SPS resources in the same subframe 200. Even when UE1 and UE2 are located in different optimal UL RX beam coverage ranges, and the base station has separate antenna arrays for simultaneously receiving from the UEs, UE1 and UE2 may be allocated their respective SPS resources in the same subframe 200.
However, the movement of the UEs may frequently vary the TX beams/RX beams that are used for transmission/reception in the beamforming system. If the RX beam of the base station varies, the allocated UL SPS resource allocations may be required to change. For example, where the UL RX beam covering UE1 and UE2 is varied when the base station lacks separate antenna arrays to receive from UE1 and UE2, the allocated UL SPS resource allocations need to be varied for UE1 and UE2. The variations in the optimal TX beams of the UEs do not require variations in the allocated UL SPS resource allocations. The allocated UL SPS resource allocation may be required to frequently update depending on the width of RX beam of the base station and the movement of the UEs, and this may defeat the purpose of SPS.
Thus, a need exists for enhancing the SPS-based resource allocation method and procedure in conventional beamforming systems.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.